British Pat. No. 2,027,691 discloses cephalosporin antibiotics shown by the following general formula ##STR5## and it is described therein that these antibiotics are highly active to gram-negative bacteria. Also, Belgian Pat. No. 878,433 discloses amino-thiazolyl cephalosporin derivatives shown by the general formula ##STR6## and it is described that they are active to gram-positive bacteria and gram-negative bacteria.
Furthermore, Belgian Pat. Nos. 853,545; 865,632; 866,038; 878,637; etc., disclose antibiotics having an .alpha.-thiazolyl-.alpha.-oximino-acetamido group as the substituent of the 7.beta.-position of cephalosporin derivatives.